Digital light processing 3D printing of polymerizable ionic liquids towards carbon capture applications

This study presents new 3D printable materials based on ad-hoc synthesized photocurable imidazolium ionic liquids (ILs) with bis(trifluoromethanesulfonyl)imide (NTf₂)⁻ as counterion and two different alkyl chain's structures at the cation, with enhanced CO₂ capture properties. The molecular structure of the synthesized ILs was confirmed through NMR technique and a polymerization study was carried out, by means of photorheological tests and FT-IR analyses, on formulations containing a crosslinking monomer (PEGDA). The study confirmed the good reactivity of the formulations that makes them suitable for digital light processing (DLP) 3D printing technique. Simple membranes were then tested through high pressure CO₂ uptake analysis to estimate their capture efficiency, comparing the results with the standard room temperature ionic liquid (RTIL) counterpart, and evidencing an increase of CO₂ absorption regardless the pressure applied. At last, complex gyroid-like structures incorporating the synthesized ILs were successfully 3D printed, showing the remarkable ability of these materials to be processed with 3D printing technology while maintaining the great CO₂ capture performances of ionic liquids. This preliminary work paves the way for the implementation of “ad-hoc” designs to create filters or devices to enhance the CO₂ capture.